Effects of gaseous chlorine dioxide on redox status in energy production and free radical scavenging of ‘Daw’ longan pericarp during storage

ผลของก๊าซคลอรีนไดออกไซด์ต่อสถานภาพรีดอกซ์ในการผลิตพลังงานและการกำจัดอนุมูลอิสระของเปลือกผลลำไยพันธุ์ดอระหว่างการเก็บรักษา

Name: Athiwat Chumyam

Classification :.DDC: 634.0994

LCSH: Longan

LCSH: Tropical fruit

LCSH: Antioxidants

Abstract: Redox status in mitochondrial energy production and free radical scavenging capabilities play a pivotal role in responding to physiological and environmental changes and metabolic control. Changes of redox potential in mitochondria and free radical scavenging may associate with oxidative stress leading to plant senescence. The aims of this study were (1) to demonstrate the involvement of an alteration of the redox status in energy production and free radical scavenging and fruit senescence of longan (Dimocarpus longan Lour. cv. Daw) during storage and (2) to investigate the effects of gaseous chlorine dioxide (ClO2) both on the redox status in energy production and free radical scavenging and on delaying senescence. Effects of ClO2 on redox status in energy production during storage of ‘Daw’ longan fruit were first examined. Freshly harvested longan fruits were fumigated with 0 (control), 5, 10 or 25 mg L-1 ClO2 for 10 minutes and then stored in a cardboard box at 25±1°C with 82±5% relative humidity for 7 days. Adenosine triphosphate (ATP) content and energy charge (EC) as well as the activities of respiratory enzymes such as succinate dehydrogenase (SDH) and cytochrome c oxidase (CCO) in the untreated control fruits were found to be steadily decreased during storage. These reductions coincided with the decrease in redox status as determined by nicotinamide adenine dinucleotide (NAD+/NADH) and ubiquinone (Q/QH2) ratios and with fruit senescence evaluated from pericarp browning and the onset of disease. However, ATP content, EC, SDH and CCO activities as well as NAD+/NADH ratio of the fumigated group were immediately and markedly increased after treatment. The effects can be seen up to 4 days of storage. No change in the Q/QH2 ratio was observed but it increased after 4 days of fumigation. Higher concentrations of ClO2 (10 and 25 mg L-1) were found to be more effective than the lower one (5 mg L-1). This indicated that altered redox state and increased energy by ClO2 were associated with a delay in fruit senescence during storage. The effects of ClO2 treatment on free radical scavenging in ‘Daw’ longan fruits stored at 25±1°C with 82±5% relative humidity was then investigated. Fresh longan fruit were fumigated with 0 (control), 5, 10 and 25 mg L-1 ClO2 for 10 minutes and then stored in cardboard box as previously described. Redox status, determined by ASA/DHA, GSH/GSSG and NADPH/NADP+ ratios, was found to be steadily decreased in the control fruits during storage. However, these ratios increased rapidly and immediately after treatment and declined steadily afterwards. The activities of NADPH-generating enzymes including glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase and ASA-GSH cycle enzymes, including ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase and glutathione reductase were upregulated depending on the concentration of ClO2. ClO2 treatment also decreased hydrogen peroxide content and fruit senescence, including browning and the onset of disease symptoms of pericarp during storage. Higher concentrations of ClO2 (10 and 25 mg L-1) were more effective than the lower one (5 mg L-1). These results indicated that redox balance in energy production and free radical scavenging directly associated with longan senescence and ClO2 could restore the redox balance in energy production and free radical scavenging, leading to reduction and delay in ‘Daw’ longan fruit senescence during storage.

Chiang Mai University Library

Address: CHIANG MAI

Email: cmulibref@cmu.ac.th

Name: Danai Boonyakiat

Role: Chairman

Name: Sujitra Ratanamarno

Role: Member

Name: Kobkiat Saegnil

Role: Member

Name: Jamnong Uthaibutra

Role: Member

Name: Lalida Shank

Role: Member

Created: 2016

Modified: 2020-01-04

Issued: 2020-01-04

วิทยานิพนธ์/Thesis

application/pdf

CallNumber: Th 634.0994 A871E

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degree

Descipline: Biology

Grantor: Chiang Mai University

©copyrights Chiang Mai University

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